Fittings of the initially cited type allow an adjustment, established by the gear unit, of the fitting top part relative to the fitting bottom part by driving the drive shaft, wherein components that can be articulated thereto can be adjusted by the relative movement of the two fitting parts relative to each other.
The area of application of such fittings can vary widely, and their use is also conceivable e.g. in the area of drives for blinds. The primary area of use of the generic fittings relates, however, to the adjustment of motor vehicle seats, the fittings being used to adjust motor vehicle seat components relative to each other. A typical area of use is to use the fittings as backrest adjusters, seat inclination adjusters, or seat height adjusters.
Particularly when the fitting is used for adjusting devices of a motor vehicle seat, it must be ensured that the fitting top part is arranged on the fitting bottom part in a secure position even in a crash in order to keep the seat from collapsing. The disadvantage of known seat fittings of the aforementioned type is that, in certain circumstances, they do not withstand loads acting in an axial direction in the installed position. Consequently, the fitting top part separates from the fitting bottom part which can be associated with a deformation of the seat structure that affects safety. The drive shaft which substantially retains the position of the fitting top part and fitting bottom part relative to each other and which rests e.g. on a shaft shoulder on one side and on the fitting via a lock ring on the other side, the lock ring being arranged on a shaft end extending through the fitting, as well as the additional arrangement of a retaining ring, are not suitable for reliably securing the position of the fitting parts in a crash.